Field of Technology
The present disclosure relates to a gate driver and a display device including the same.
Discussion of the Related Art
An electroluminescent display is classified into an inorganic electroluminescent display and an organic electroluminescent display depending on a material of an emission layer. An active matrix organic light emitting diode (OLED) display includes a plurality of OLEDs capable of emitting light by themselves and has many advantages of fast response time, high emission efficiency, high luminance, wide viewing angle, and the like.
An OLED display includes pixels arranged in a matrix and adjusts a luminance of the pixels in accordance with gray levels of image data. Each pixel includes an OLED, a driving thin film transistor (TFT) controlling a driving current flowing in the OLED depending on a gate-to-source voltage of the driving TFT, and switching TFTs programming the gate-to-source voltage of the driving TFT in response to a scan signal. The pixel adjusts a display gray level (or a luminance) with an amount of light emitted by the OLED proportional to the driving current. Each pixel may further include an emission TFT that is turned on or off in response to an emission signal and determines emission timing of the OLED.
The OLED display includes a scan driver generating the scan signal and an emission driver generating the emission signal. The scan driver and the emission driver constitute a gate driver.
The scan driver sequentially supplies the scan signals to first gate lines. Gate electrodes of the switching TFTs are connected to the scan driver through the first gate lines. The emission driver sequentially supplies the emission signals to second gate lines. Gate electrodes of the emission TFTs are connected to the emission driver through the second gate lines.
The emission driver may be implemented as a gate shift register including a plurality of stages. Each stage outputs the emission signal at a gate-on voltage or a gate-off voltage depending on a voltage of a node Q and a voltage of a node QB. The emission signal of the gate-on voltage is a signal capable of turning off the emission TFTs, and the emission signal of the gate-off voltage is a signal capable of turning on the emission TFTs. The emission signal of the gate-on voltage is output while the node Q is activated, and the emission signal of the gate-off voltage is output while the node QB is activated.